Observations on Retest Discrepancy in Mentally Sub‐normal Children

S ummary . Retest scores of subnormal children were examined in order to check the reliability of previous retests and to estimate to what extent the discrepancies might reflect real changes in the rate of mental development as well as errors of standardization. The discrepancies were considerably greater than those obtained from the standardization of the Binet by Terman and Merrill. The usual tendency towards increasing discrepancy with time‐interval was confirmed, except for an apparent practice‐effect at short intervals. The gains and losses were much more heterogeneous than could be accounted for by intra‐test error. Boys lost significantly less than girls. It was concluded that the retest discrepancies might in large part be due to real variations in the rate of mental development (including such as are dependent on changes in motivation)

Developmental psychology · Mentally retarded · Standardization · Test (biology) · Psychology · Psychometric Methodologies and Testing